Constant-speed mechanism



March 17. 1925.

C. I. HALL CONSTANT SPEED MECHANISM.

Filed June 14, 1921 Invenlior: Chester I. Hall,

His Attorney;

Patented Mar. 17, 1925.

UNITED STATES I 1,530,259 PATENT OFFICE.

CHESTER I. HALL, OF FORT WAYNE, INDIANA, ASSIGNOR TO GENERAL ELECTRICCOM- lPANY, A CORPORATION OF NEW YORK.

CONSTANT-SPEED MECHANISM.

Application filed. June 14, 1921. Serial No. 477,605.

To all-whom it may concern:

Be it known that I, CHESTER I. HALL, a citizen of the United States,residing at Fort Wayne, in the county of Allen, State of Indiana, haveinvented certain new and useful Improvements in Constant-SpeedMechanism, of which the following is a specification.

My invention relates toa constant speed mechanism and more particularlyto such a mechanism used in connection with elecbe used, a clock or itsequivalent must be used. An ordinary mechanical clock is disadvantageoussince it must be wound up by hand periodically, and it.may not runisochronously from the condition when it is fully wound to the conditionwhen it is nearly run down. In these types of instruments it has beenproposed to use a constant speed motor, or a motor -so arranged that itwinds the springs of a clock movement at periodic intervals. On ordinarycircuits it is extremely difficult to control a motor in such a way thatits speed remains so nearly constant that it may become useful as asubstitute for a clock. On

the other hand, periodicallyv energized motors require contacts to bemade and broken. These contacts become unreliable after a long period ofservice, and replacements are often necessary.

It is the main object of my invention to make it possible'to utilize anelectric motor for keeping the clock spring wound, with-' out it beingnecessary to have contacts made or broken. I vention to prevent themotor frominjurlng permanently the spring of the constant speedmechanism by overwinding. I attain these objects by interposing amechanical connection between the winding motor and It is another objectof my in-- the spring so arranged that-it comprises substantially arigid connection while the spring is not in its fully wound condition.When the spring is fully wound this connection is so arranged that theenergy supplied by the motor as well as its kinetic energy of rotationare absorbed in another way than by an action on the spring. I find itadvantageous to use a motor having series characteristics; that is, onein which the speed of the motor decreases rapidly as the torqueincreases. When such a motor is used, while the spring is being woundthe speed is comparatively great,- since the torque is small. As thetorque increases, the speed of the motor is reduced.v When the spring isfully wound, if no precautionary measures would be taken, the motorwould exert such a strong torque that the spring would break. Theconnection mentioned heretofore is so arranged that the energy of themotor is absorbed after the spring is fully wound by friction betweentwo surfaces, The friction between these twosurfa'ces, however, is sogreat that as soon as the momentum of the motor is checked thereby, theopposing force due to this friction is sufiicient to bring the motortorest. It stays at rest until the spring is sufliciently unwound topermit the motor to start up again. advantage that all contacts areobviated and that there, is no danger'of the spring breaking. Further,very little energy is absorbed uselessly in friction which is not theThis arrangement'has the f:

case if the connection between the motor and spring would be aconstantly slipping one.

Other objects and advantages of my invention will become apparent as thedescription proceeds.

Fora better understanding of my invention, reference is to be had to thefollowing specification together with the accompanying drawing in whichthe single figure a distorted perspective view showing how a constantspeed mechanism embodying my an escapement wheel 9. merits-are We llknown it is not essential in any greater detail.

is connected through various mechanical it is fully wound, breaking ofthe spring connections to be described later to the-inner end ofresilient member'or spring a which serves as the actuating memlo'eri'o'fthe constant speed mechanism. 'The outer end of the spring 4 is soarranged that it drives a constant speed shaft 5. To cause this shaft 5to have a constant speed; an escapement mechanism shown generally isthenumeral -6 is utilized. In the present' stance .a .marine'es'cap'ement is shown eomprisinga balance Wheel 7, VergeS and Since suchescapeto describe thisportionhof the mechanism Wheel 9 ismechanicallyconnected as by the ge arin'g 10 to a 1:1 rigidly connected to theconstant speed shaft 5, which gear 11 ialsoserves to-supplyan-anchori'ngzpoint for the spring- 4.

i ,r in

"theouter Zen (1 0i the spring-e.

The small :se'i 'ies motor 3 is connected neross the conductors 1 and 2through a connecting means such as the switch '12. The current fromconductor 1floWs'=through the li-eld coil 13 oiithe lnotor,'tlienfrointhe field coil through brushes 14:, through the armature andcommutator 16, through the other set 0f brushes 17, back to the line--tlir'o'ugli theswitch "12. By'means of gears "18, 19, 20, 21, 22 andn3 the speed'ol'themotor sl alt 24 is suiii'ciently reduced so that'the"energy-supplied by the IDOiIOl may be ut-i-l-ized to Wind upthe'inn'er end of The entire motor 3 is 01'' very small size, -si ncebut little 'red therefrom. 7 1n is rigidly connected to a shaft 25"connected-Ito the inner end of .the springs, as c a rlysh-own "onthedrawing.= The shaft to which ge ar -20 is "fa-s en-ed in the "train ofgears bet-Ween the shaft 2 1-.

is :not ri idly connected to and the sham The escapement The l est ge'argear 19' in the train but insteael it 'is rigidly connected toa disc 27of some inaterial which a large coellicient-of tr-ictionwitlr respect tothe metal surface of gear 19.-

disc 27 e-nd'the gear 1.9 are pressed together" when assembled so thatthere is substan tially ia irigid connection between them until the"torque exerted by the mot'or 3 becomes abnormally egreat To prevent"the spring 4 from unwinding it for any reason the motor he disoonn ectedfrom the source, I provide a T128 pivoted bathe stationaryupivot 'gethenThe entire niechanism operstanth being Wound and ist supplied Withsubstantially allxof the: energy developed motor 3 until it is fullyWound. When holdrlmg the/disc??? and theigear 19close= vide'd.

is prevented by the connection between gear 19 and the disc 27, whichslide one upon 'the other until the motor 3 is gradually hrou'gh't torest; The spring has sufficient length that-it may run for anappreciable time even after the circuit 1-2 is interrupted.

The constant speed mechanism is utilized in the present =lnstance todrive at a const'an-t speeda"rotatable cam 31 in the direction shoWn -bythe arrow thereon; The

interval required for a complete revolution of the-021 111 81may be 15or 30 minutes or any other length of time-during WlilCll- 1t isdesiredto'ineasure-the amount of energy expended in an electric circuit. Thecam 31' has araised portion arranged to coact withaiprvotedlerer 3-3 forrocking it sligl'rt-' 1y oneefor each revolution-of the cam 31.

The demand indicator illustrated in "the present instancecomprisesascale 34% and acoopcrating non-return"pointer 35' arranged tobe driven by an actuator 36:

'UlOSOCl'llMlhQiPIQSGlIt instance o nee tor-each 'revolritioirot a-Wheel "ill by means of the stationary contact 4L2 a-nd the contact s3'n'iountetl'on th'e' wh-eel" 4:1. The Wheel 41 carrying'the contact4S'is SllOifIl in this instance as directly geared to a spindle 44 aWatthour meter'not shown. It is evident that upon' equal expenditures ofenergy measured by the w 'tthour meter-correspond ngto one re'volu on erwheel e1, the-shalt 4.4L is actuated sufficiently toina'uecontaethetween parts 42"aiid' 43 and to energize the electro mag'net'38. The electro' m'agnetfiS"then attracts the armature to-Whien" isrigidl y connected the arms which in turn carries a pivoted pawl i6'coact-ing With the ratchet wheel 4:7. It is thusevident thattor eachene'rgiZat-ion of? the' coil th'e ratchet-"Wheel 47 is advanced by a"constant 'aneount; In order 'to'prevent theratchetwheel-$1 0111rotating in a haclr Ware direction' a "pivoted ipawl 4L8 is pro- To keepiFlIQEEEEPZIWlS-Hl engagement 22) coa'ctiing with a ratchet Twheel30rigidly-w fastened to the shaft-26. The ratchet Wheel ratchet wheel 47is normally connected th-rou'gli'igears 50; 51 52 and 53' with the shaft5 h'carrying the" actuator 36. The constant "speed mechanism, however,isso arranged thatit *elisceiinreets the driving connection betweenthe'shaft 5i and the ratchet wheel 4:7 periodicalljw This isaccomrpl-ish'ed hyy the rotation; of I the pivoted lever This le'i'erhas a iork 5'5 en ;aging in the groove 56 of a slidable sleeve 57. Thissleeve carries the gear 50 and has a slidable nected from the gear 51.When this occurs,

the actuator 36 comes back to its zero position, since the shaft 54 towhich it is connected is urged to that position by means of the springwound thereon and having one end connected to a stationary post 61 andthe other end connected to the gear This zero position is determined bystationary post 63, against which the post 64 carried by gear 53 isurged when the spring 60 is free to act. 7

It is thus evident that upon equal inter vals of time the actuator 36 ismade to return to its zero position. The actuator 36 serves to pushforward the pointer 35 in case the travel of this actuator is greaterthan any it has had previously. The amount of movement of the actuator36 during these equal intervals of time is made dependent upon theamount of energy expended in any circuit by means of the electro-magnet38 and pawl and ratchet arrangement.

The particular use to which my constant speed mechanism is put isdescribed merely by wayof example. It is evident that it may be used inany other type of instrument where it is necessary to obtain a constantspeed either to indicate the time of day, to actuate a chart, or toactuate mechanism in equal intervals of time as in this case. is alsoevident that my invention is not limited to the specific embodimentshown in the drawings and I aim to embrace in the appended claims allmodifications falling fairly within the spirit and scope of myinvention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is

1. In constant speed mechanism, means for supplying energy to themechanism comprising a resilient member for storing mechanical energy, amotor active at all times for supplying energy to said member, and africtional driving connectionbetween said motor and member adjusted toabsorb suflieient of the motor energy to stop the latter after theresilient member is supplied with all the energy it can safely possess.

2. In a constant speed mechanism, means for supplying energy to themechanism comprising a spring for storing mechanical energy, aconstantly energized motor having series characteristics for winding thespring, and means whereby substantially the entire torque of said motoris used for winding up said spring, and whereby the motor after thespring is fully wound is gradually brought to rest.

3. In a constant speed mechanism, means for supplying energy to themechanism comprising a spring, a constantly energized motor active atall times for winding the spring, and a driving connection between themotor and the spring arranged to stop said motor after the spring isfully wound.

4. In a constant speed mechanism, means for supplying energy to themechanism comprising a spring for storing mechanical energy, aconstantly energized motor having series characteristics for winding thespring, and a mechanical connection between the motor and the spring soarranged that substantially all the torque of the motor is utiliz ed'forwinding the spring until it is fully wound, and that it gradually bringsthe motor to rest after the spring is wound.

In a constant speed mechanism, means for supplying energy to themechanism comprising a spring for storing mechanical energy, aconstantly energized motor having series characteristics for winding thespring, and a mechanical connection between the motor and thespring thatis substantially rigid until the spring is fully wound, but that permitsslipping thereafter until the motor comes to rest.

- In witness whereof, I have hereunto set my hand this 10 day of June,1921.

CHESTER I. HALL.

